An understanding of the epidemiology of NIDDM in Japanese Americans should take into account the likely metabolic bases for hyperglycemia. The investigators have obtained the measurements necessary to accomplish this and have done so repeatedly as an ongoing part of their longitudinal research. For this reason, they have elected to denote these investigations "metabolic epidemiology of NIDDM". Interestingly, there appear to be important gender differences in the relationships of etiologic factors to the pathogenesis of NIDDM, and in the sequence of changes. These gender differences are expressed as lower risk for NIDDM in premenopausal women and greater risk in postmenopausal women, suggesting that metabolic changes occurring during menopause may be important. Thus the overall hypothesis for this proposed research is: NIDDM in Japanese Americans results from the effects of lifestyle factors reflecting "westernization", acting upon a genetic background predisposing to the development of hyperglycemia. This interaction leads to increased visceral adiposity and insulin resistance, which in the presence of an islet beta-cell lesion, results in hyperglycemia and eventually in NIDDM. These metabolic changes are modified by gender and age. In order to address this overall hypothesis, the research has the following specific aim: to ascertain the metabolic sequelae of an important milestone of aging in women, the menopause transition, and its relationship to NIDDM by continuing for an additional 5 years their longitudinal metabolic epidemiologic study of second-generation Japanese-American women and third-generation men and women, the latter to be expanded in order to increase the number of women who are likely to enter menopause during follow-up.